obesity | VOLUME 16 NUMBER 3 | MARCH 2008 615
nature publishing group
behavior and psychology
Grazing and Loss of Control Related to Eating:
Two High-risk Factors Following Bariatric Surgery
Susan L. Colles1, John B. Dixon1 and Paul E. O’Brien1
background: Gastric restrictive surgery induces a marked change in eating behavior. However, the relationship
between preoperative and postoperative eating behavior and weight loss outcome has received limited attention.
objective: This study assessed a range of eating behaviors before and 1 year after laparoscopic adjustable gastric
banding (LAGB) and explored the nature and extent of change in eating patterns, their clinical associates, and impact
on weight loss.
Methods and Procedures: A 12-month observational study assessed presurgical and postsurgical binge eating
disorder (BED), uncontrolled eating, night eating syndrome (NES), grazing, nutrient intake and eating-related behaviors,
and markers of psychological distress. A total of 129 subjects (26 male and 103 female, mean age 45.2 ± 11.5 and BMI
44.3 ± 6.8) participated in this study.
Results: Presurgical BED, uncontrolled eating, and NES occurred in 14%, 31%, and 17.1% of subjects, which reduced
after surgery to 3.1%, 22.5%, and 7.8%, respectively (P = 0.05 for all). Grazing was prevalent before (26.3%) and after
surgery (38.0%). Preoperative BED most frequently became grazers (P = 0.029). The average percentage weight loss
(%WL) was 20.8 ± 8.5%; range −0.67 to 50.0% and percentage of excess weight loss (%EWL) 50.0 ± 20.7%; range
−1.44 to 106.9% (P < 0.001). Uncontrolled eating and grazing after surgery showed high overlap and were associated
with poorer %WL (P = 0.008 and P < 0.001, respectively) and elevated psychological distress.
Discussion: Consistent with recent studies, uncontrolled eating and grazing were identified as two high-risk eating
patterns after surgery. Clearer characterization of favorable and unfavorable postsurgical eating behaviors, reliable
methods to assess their presence, and empirically tested postsurgical intervention strategies are required to optimize
weight loss outcomes and facilitate psychological well-being in at-risk groups.
Obesity (2008) 16, 615–622. doi:10.1038/oby.2007.101
The two most common bariatric procedures today are lap-
aroscopic adjustable gastric banding (LAGB) and roux-en-Y
gastric bypass. Both surgeries involve a gastric restrictive com-
ponent that generates a predictable reduction in total energy
intake (1–3), and a reliable, though variable, weight loss in the
first postoperative year and beyond (4). In the case of LAGB,
the primary weight loss mechanism is thought to be the induc-
tion of satiety (5). A marked reduction in hunger has also been
reported (6). Increased feelings of satiety and low hunger lev-
els would facilitate the sustained behavior modification that
is required to achieve a long-term change in energy balance
(7,8). It is currently in question whether certain preoperative
eating behaviors render affected individual less responsive to
these effects and influence the efficacy of bariatric surgery (9).
Binge eating disorder (BED) has been the focus of most
studies to examine links between preoperative eating patterns
and surgical outcome. BED involves repeated uncontrolled
episodes during which objectively large amounts of food are
consumed, in association with marked emotional distur-
bance (10). Prospective studies to assess preoperative BED
reveal no consistent predictors of postsurgical weight loss
(1,11–13). Following gastric restrictive the ability to consume
objectively large amounts of food in a single sitting is impeded,
and BED prevalence is greatly diminished (14,15). Yet feel-
ings of loss of control (LOC) related to eating can still persist
(16,17). It is uncertain whether preoperative binge eaters are
more likely to experience postsurgical feelings of LOC or how
recurrent episodes of LOC influence weight loss and psycho-
logical state. We have previously found that emotional distur-
bance related to feelings of LOC, even while eating subjectively
large amounts of food, was common among surgical candi-
dates, and predicted by markers of psychological distress (18).
The night eating syndrome (NES), characterized by morn-
ing anorexia, evening hyperphagia and sleep difficulty, and
more recently by recurrent awakenings from sleep to eat (19),
1Monash University, Centre for Obesity Research and Education (CORE), Alfred Hospital, Melbourne, Victoria, Australia. Correspondence: Susan L. Colles
Received 30 May 2007; accepted 27 August 2007; published online 17 January 2008. doi:10.1038/oby.2007.101
VOLUME 16 NUMBER 3 | MARCH 2008 | www.obesityjournal.org
behavior and psychology
has received limited attention (20–22). This pattern of eating
appears associated with obesity and prevalent among obese
treatment seekers, yet the impact of NES on bariatric surgery
is unknown (19).
The consumption of smaller amounts of food over extended
periods of time has also been described before (6,8,11,12,17,23)
and after obesity surgery (17). This eating pattern has been
commonly termed “grazing.” Preoperative binge eaters may be
high risk to convert to postoperative grazing (11,17). As an eat-
ing pattern, and a potential contributor to weight gain, grazing
has received minimal attention. This is particularly surprising
in the surgical sphere, given that the consumption of small
amounts of food continuously over extended periods is not
precluded following bariatric surgery.
This study prospectively assessed characteristics of BED,
uncontrolled eating, NES and grazing, before, and 1 year after
LAGB. We aimed to explore the nature and extent of change
in these eating patterns following surgery. The impact of pre-
surgical and postsurgical eating behavior on weight loss was
the primary outcome measure. Any associations between eat-
ing behavior and markers of psychological distress were also
of interest. To provide further description, energy intake and
additional eating-related factors were recorded.
Methods and procedures
The study was of a prospective observational design. Data were collected
primarily via a series of self-report questionnaires, completed before
and 12 months after LAGB. At baseline, confirmation of the presence of
features of BED, feelings of LOC, NES, and grazing took place during a
semistructured clinical interview. At 12-month follow-up eating behav-
iors were confirmed during a semistructured phone interview.
The study was approved by the Monash University Standing Com-
mittee on Ethics in Research involving Humans and was conducted in
accordance with the Helsinki Declaration of 1975, as revised in 1983.
Between August 2004 and December 2005, severely obese persons
accepted into the bariatric surgery program at The Avenue Hospital,
Melbourne, were invited to participate. Subjects were male or female
aged between 18 and 65 years. Individuals were not eligible to take part,
if they had undergone previous bariatric surgery. All participants pro-
vided informed, written consent.
A single experienced surgeon placed the Lap-Band System ( Allergan
Health, Irvine, CA) along the pars flaccida pathway. The band was secured
around the upper part of the stomach just below the gastroesophageal
junction to create a small upper gastric pouch. After a 5-week periop-
erative period, the balloon of the band was gradually inflated to induce
gastric restriction and promote feelings of between-meal satiety and early
satiation (24). According to standard clinic protocol, in the first year,
subjects were encouraged to visit the clinic every 2 weeks for the first
1–2 months, then monthly, and quarterly as required.
Anthropometry. Height was recorded at baseline to the clos-
est millimeter using a wall-mounted stadiometer. Body weight
was recorded at baseline, 4 and 12 postsurgical months to the
nearest 0.1 kg, using the electronic Tanita Wedderburn TBF-305
(Lake Worth, FL), in light clothing without shoes. Weight loss was
reported as the percentage weight loss (%WL) at 12 months after
LAGB. For further description, the percentage of excess weight loss
(%EWL) has also been reported. The %EWL was calculated by divid-
ing the weight loss in kilograms by the excess weight (the initial weight
minus weight at BMI 25) and multiplying this figure by 100.
Assessment of BED and an LOC related to eating. The Ques-
tionnaire on Eating and Weight Patterns–Revised (QEWP-R) (25,26)
was used to screen for binge eating behavior. Subjects who reported
any characteristics of a binge underwent a semistructured clinical
interview at baseline and a phone interview at 12-month follow-up. A
single, experienced clinician performed all interviews. The quantity of
food consumed, whether a sense of LOC was present, the extent of the
associated distress, and the frequency of objective and subjective binge
episodes was established. To assess the extent of distress associated with
feelings of LOC related to eating, subjects self-rated their emotional dis-
turbance on a scale measuring distress. Scores ranged from 1 (no dis-
turbance) to 5 (extreme disturbance). A score of 4 or 5 was considered
to indicate a high level of self-reported emotional disturbance (18).
Before and after surgery, “Full BED” subjects met all diagnostic criteria
for BED as outlined in the Diagnostic and Statistical Manual of Mental
Disorders, 4th Edition (10). They reported a frequency of ≥2 objective
bulimic episodes/week over the previous 6 months in association with
behavioral markers of LOC and significant psychological distress. The
term “Uncontrolled Eaters” was given to the group who experienced feel-
ings of LOC during the consumption of either a subjectively or objec-
tively large amount of food at a frequency of ≥1/week over the previous
6 months but did not meet full BED criteria. The level of psychological
distress associated with the bulimic episodes was variable. After reas-
sessment of eating behavior at 12 months, the few subjects who met full
BED were combined with those meeting the criteria for “Uncontrolled
Eaters.” The postsurgical group was labeled “Uncontrolled Eaters_12.”
“Uncontrolled Eaters_12” represented a group who experienced postsur-
gical feelings of LOC related to eating. “Non-binge eaters” reported no
sense of LOC during the consumption of either subjectively or objectively
large amounts of food.
The NES. A self-made survey screened for NES based on the pro-
posed diagnostic criteria of Stunkard et al. in 1996 (27). NES diagnosis
required that persons usually (i) had no appetite for breakfast, (ii) con-
sumed 50% or more of total energy intake after 7 p.m., and (iii) had
trouble getting to sleep or staying asleep on three or more nights of the
week within the previous 3-month period. The consumption of noctur-
nal snacks during night time awakenings was also assessed. NES behav-
iors were confirmed by interview.
“Grazing” behavior. A pattern of “grazing” was measured primar-
ily to investigate the association between small amounts of food eaten
over continuous periods and postsurgical energy intakes and weight
loss outcomes. The definition of grazing was based on that reported by
Saunders (8,17). Grazing was defined by the consumption of smaller
amounts of food continuously over an extended period of time, eat-
ing more than the subjects considers best for them. At baseline and
follow-up, subjects were asked whether they had often engaged in a
grazing pattern of eating during the previous 6 months. Grazing was
confirmed by interview.
Other eating behavior. The Cancer Council Victoria Food Frequency
Questionnaire (28,29) was used to assess subject’s usual dietary habits
and derive a total energy intake. Validity of the Cancer Council Victoria
Food Frequency Questionnaire relative to 7-day food records has
proven acceptable (28). The highest and lowest 2% of calculated energy
intakes at baseline and 12 months were excluded from statistical analy-
sis. The Three-Factor Eating Questionnaire (30) collected information
on cognitive dietary restraint, disinhibition of eating, and subjective
feelings of hunger. A series of multiple choice questions and dichoto-
mous response items collected additional information. Before and after
surgery, subjects indicated how many times a day they ate, consider-
ing all meals and snacks as a separate “eating episode.” The frequency
of gastrointestinal symptoms after surgery was also assessed. Based on
obesity | VOLUME 16 NUMBER 3 | MARCH 2008 617
behavior and psychology
the definition of Busetto et al. (1), vomiting was defined as disgorging
the contents of the stomach or esophagus through the mouth. Obstruc-
tion was defined as a temporarily blockage of the Lap-band outlet. At
analysis, the reported frequency of both symptoms were combined.
After surgery, subjects were asked to indicate from a list, situational
or emotional factors that predisposed them to consume types of foods
or quantities of food they knew to be not best for them. The fear of
weight regain, and the perceived return of “old eating habits,” were also
assessed. At four postsurgical months, subjects were sent a short ques-
tionnaire asking how many times a day they ate and the frequency of
gastrointestinal symptoms. Failure to return the 4-month questionnaire
did not result in study exclusion.
Psychological health and quality of life (QoL). The Beck Depres-
sion Inventory (31) assessed for the presence of symptoms of depres-
sive illness. A score of 0–9 was considered “Normal”; 10–16 “Mild
depression”; 17–29 “Moderate depression”; and 30–63 “Severe depres-
sion” (32). The Multidimensional Body Self-Relations Question-
naire (33) provided a measure of body image distress. The difference
between the appearance orientation subscale (how one values physi-
cal appearance in general) and the appearance evaluation subscales
(how one rates their own physical appearance) was used to indicate
the degree of appearance dissatisfaction (34). The Medical Outcomes
Trust Short Form-36 (SF-36) was used to assess health-related QoL
(35,36). Results of the survey are presented as the SF-36 physical and
mental summary scales (36).
Postsurgical complications. Any band slippage and port access prob-
lems requiring revisional surgery were noted.
Descriptive statistics were used to express the mean ± s.d. for con-
tinuous, normally distributed variables. Baseline and 12-month Beck
Depression Inventory scores and the Three-Factor Eating Questionnaire
hunger score at 12 months were not normally distributed and required
log transformation. Differences between anthropometric, psychologi-
cal, and eating-related measures before and after surgery were tested
using paired Student’s t-tests for continuous variable and χ2-test for
categorical variables. Differences between respondents and non-
respondents (those who did not return the 12-month survey), and
between the eating subgroups and the remainder of the cohort were
tested using Independent t-tests for continuous variables, χ2-test for
categorical values, and Mann–Whitney U-test for ordinal data. The
change in eating category before and after surgery, and differences in
postsurgical emotional and situational eating triggers between groups
were assessed using the χ2-test. Forward and backward linear regres-
sion explored which preoperative and postoperative factors predicted
weight loss outcome. Both models controlled for age, gender, baseline
BMI, and insulin resistance (37). Key variables were grouped accord-
ing to postoperative eating pathology, energy intake, eating behavior,
and markers of psychological distress. SPSS version 12.0.1 was used for
statistical analysis. A P value of <0.05 was considered statistically signi-
ficant. A P value of >0.05 and <0.10 was considered a statistical trend.
respondents and non-respondents
Of 180 subjects recruited at baseline, 6 did not go on to have
surgery, 1 died of myocardial infarction, and 44 failed to
return the 12-month survey. All eligible subjects (n = 173)
were notified by phone before the 12-month survey was sent
and then contacted by phone to prompt survey completion
between one and three times. In total, 129 subjects returned
the baseline and 12-month surveys, representing a response
rate of 75%. The postoperative survey was returned on average
12.29 ± 1.1 months after surgery. Comparison of eligible sub-
jects who returned and who did not return the final question-
naires showed a lower %WL (P = 0.009) in non-responders.
This group was also more likely to have been diagnosed with
BED preoperatively (P = 0.033) and to have attended less clinic
appointments (P = 0.017).
Mean age of the participants was 45.2 ± 11.5 years, with a gen-
der distribution of 103 females (80%) and 26 males. Table 1
lists clinical, behavioral, and psychological characteristics of
subjects at baseline and 12 months. Over the first postsurgical
year mean body weight reduced from 122.2 ± 20.5 kg (range
75.1–201.2) to 98.5 ± 18.2 kg (range 56.8–152.9) (P < 0.001).
The mean %WL was 20.8 ± 8.5% (range −0.67 to 50.0%) and
mean %EWL was 50.0 ± 20.7% (range −1.44 to 106.9%).
Concurrent with the average decline in body weight, the prev-
alence of BED and NES, and severity of subjective hunger and
dietary disinhibition, symptoms of depression, and appearance
dissatisfaction all reduced significantly. Dietary restraint and
health-related QoL increased. The prevalence of grazing did
Subjects attended clinic 11.75 ± 3.7 times and underwent
7.88 ± 3.4 band adjustments. The annual number of clinic vis-
its or band adjustments did not differ according to baseline or
postsurgical eating pathology. Anterior prolapse of the band
occurred in two subjects (1.6%), and port access problems
requiring replacement occurred in three subjects (2.4%). The
complication rate was too low to assess for any association with
table 1 clinical, behavioral and psychological characteristics
of the total cohort before and 12 months after laGB (n = 129
Baseline 12 Months
Mean BMI44.3 ± 6.8a
35.0 ± 6.0***
Binge eating disorder 18 (14.0%)4 (3.1%)*
Uncontrolled eaters 40 (31.0%) 29 (22.5%)*
Night eating syndrome22 (17.1%) 10 (7.8%)*
Grazer 34 (26.4%)49 (38.0%)
BDI score15.0 (10–21)b
AD score 1.7 ± 1.00.91 ± 1.0***
Appearance orientation3.5 ± 0.69 3.5 ± 0.64
Appearance evaluation 1.8 ± 0.662.6 ± 0.82***
SF-36 MCS 46.9 ± 8.1 48.9 ± 7.3*
SF-36 PCS 37.2 ± 10.049.2 ± 9.8***
Restraint 8.3 ± 3.9 13.0 ± 4.2***
Disinhibition11.5 ± 3.4 6.2 ± 3.9***
Hunger9.0 (6–12) 2.0 (1–5) b,***
Statistical analysis using paired Student’s t-tests for continuous variables and
Chi-square for categorical variables.
AD, appearance dissatisfaction; BDI, Beck depression Inventory; MCS, mental
health component score; PCS, physical component score.
aMean ± s.d. (all such values); bData presented as median (IQR); analysis based
on log transformed values. *P < 0.05, **P < 0.01, ***P < 0.001.
VOLUME 16 NUMBER 3 | MARCH 2008 | www.obesityjournal.org
behavior and psychology
At baseline BED was diagnosed in 18 study participants
(14%). Compared to the remainder of the cohort, baseline
BED were distinguished by higher symptoms of depression
(P = 0.033), appearance dissatisfaction (P = 0.05), dietary dis-
inhibition (P < 0.001), and hunger (P < 0.001). They reported
more frequent daily eating episodes (P = 0.001) and con-
sumed a higher usual energy (P = 0.023) and percentage fat
(P = 0.006) intake compared to the remainder of the cohort.
Despite these initial differences, the group with baseline BED
were not characterized by any eating-related or psychological
measure after surgery. A statistical trend toward a higher
monthly frequency of gastrointestinal symptoms (vomiting or
obstruction) was evident at 4 postsurgical months (P = 0.068)
but not at 12 months. Baseline BED achieved a similar weight
loss to the remainder of the cohort (%WL 21.9 ± 11.1% vs.
20.6 ± 8.1% and %EWL 52.5 ± 25.8% vs. 49.6 ± 19.8%). After
surgery the majority of baseline BED (n = 11; 61.1%) were
newly categorized as grazers, and eight subjects (44%) were
classified as “Uncontrolled Eaters_12” (Table 2). Seven of the
eight “Uncontrolled Eaters_12” were also classed as postop-
erative grazers. One-third of baseline BED (n = 6) reported no
postsurgical eating pathology.
Twelve months after surgery four subjects (3.1%) met full BED
criteria. Two of these subjects had been diagnosed with base-
line BED, and two had not. As they were too few for statistical
analysis, those with BED were combined with “Uncontrolled
Baseline uncontrolled eaters
“Uncontrolled Eaters” were common before surgery (31%).
This group reported elevated preoperative hunger (P < 0.001)
and disinhibition (P < 0.001), consumed a higher usual energy
intake (P = 0.035) and tended to a higher percentage fat
intake (P = 0.068) compared to non-binge eaters. No presur-
gical psychological or weight-related measures distinguished
“Uncontrolled Eaters.” However, Table 2 shows that a signifi-
cant percentage of this group were identified with this eating
pattern after surgery. Ten of the fourteen subjects who con-
tinued uncontrolled eating after surgery also met criteria for
grazing. Baseline “Uncontrolled Eaters” lost a similar %WL to
postsurgical uncontrolled eaters
After surgery, 29 subjects (22.5%) reported feelings of LOC
≥1/week during the consumption of a subjectively or objec-
tively large amount of food, during the previous 6 months.
This group and the four subjects with BED were combined
and labeled “Uncontrolled Eaters_12.” Table 3 shows that
“Uncontrolled Eaters_12” were a distinctive group who
achieved a significantly lower weight loss, equating to a mean
loss of 21.6 kg vs. 26.7 kg in the remainder of the group. The
“Uncontrolled Eaters_12” consumed a higher usual energy
intake and percentage of energy as fat and ate more often over
the day. They reported less dietary restraint and greater hun-
ger and disinhibition. Importantly, symptoms of depression
were also higher, and mental health-related QoL was poorer
compared to the remainder of the cohort. Results were similar
when the four subjects with BED were excluded from analysis
(data not shown).
severe distress related to uncontrolled eating
Twenty-five subjects (76% of “Uncontrolled Eaters_12”) reported
a high level of emotional disturbance related to their feelings
of LOC. This subset of “Uncontrolled Eaters_12” was signifi-
cantly younger than the remainder of the cohort; mean age 39.1
± 12.4 years compared to 46.7 ± 10.8 years (P = 0.003). They
also reported great dissatisfaction with appearance (P < 0.001),
recorded a higher BMI at every time point (all P < 0.05), and
showed a statistical trend toward female gender (P = 0.090).
At baseline, 22 subjects (17.1%) fulfilled NES criteria, and 10
subjects (7.8%) reported frequent nocturnal snacking. Men
were more likely to be night eaters than women (P = 0.008),
and NES was commonly associated with BED (P = 0.048), as
previously reported (38). Baseline NES were not distinguished
from the remainder of the cohort by any psychological or eat-
ing-related measure and lost a similar %WL. Baseline NES did
not predict postsurgical night eating, uncontrolled eating, or
grazing (data not shown).
Ten subjects (7.8%) reported NES at 12 months (Table 1). Of
these, only four were baseline NES (18.1%), and an additional
table 2 overlap between presurgical and postsurgical eating
BED (n = 18)
eaters (n = 40)
grazer (n = 34)
n = 4
n = 2
n = 1
n = 3
P = 0.035NS
P = 0.025
n = 33
n = 8
n = 14
n = 22
P = 0.048
P = 0.018
P < 0.001
n = 49
n = 11
n = 16
n = 32
P = 0.029NS
P < 0.001
Postsurgical Upset re: LOC
n = 25
n = 5
n = 10
n = 10
P = 0.085
No Grazing or LOC after surgery
n = 73
n = 6
n = 20
n = 1
P = 0.032 NS
P < 0.001
Statistical analysis using χ2 for categorical variables.
BED, binge eating disorder; LOC, loss of control; NS, not significant.
aGroup numbers include four subjects with postsurgical BED.
obesity | VOLUME 16 NUMBER 3 | MARCH 2008 619
behavior and psychology
six subjects began experiencing this cluster of behaviors after
surgery. There were no gender differences in this postsurgical
group; however they reported lower cognitive restraint (P =
0.042) and a lesser consumption of “hard” foods (P = 0.032)
and protein (P = 0.05). Weight loss was not statistically sig-
nificantly different to non-NES, yet the mean %WL in night
eaters was 16.9% compared to 21.1%WL in non-NES, and
43.3%EWL vs. 50.6%EWL, respectively. A statistical trend
toward fewer band adjustments in NES was noted (P = 0.069).
Reports of nocturnal snacking reduced to four subjects (3.1%)
postoperatively (P = 0.033).
Prior to surgery, 34 subjects (26.4%) reported a grazing pattern
of eating. Grazing was associated with lower dietary restraint
(P = 0.025), higher dietary disinhibition (P < 0.001) and
hunger (P = 0.034), and more frequent daily eating episodes
(P = 0.05). At 12-month follow-up, baseline grazers reported
significantly more symptoms of depression (P = 0.033) and had
lost less weight (%WL 15.7 ± 7.8% vs. 22.6 ± 8.0% and %EWL
37.3 ± 19.0% vs. 54.6 ± 19.3%) compared to the remainder of
the cohort (P < 0.001). Presurgical grazers were highly likely
to continue grazing; 94.1% of preoperative grazers continued
to report this eating pattern after surgery (Table 2). In addi-
tion to postsurgical grazing, 65% of baseline grazers also met
criteria for “Uncontrolled Eaters_12.”
After surgery, 49 subjects (38%) reported grazing (Table 1).
Although this figure was not statistically different from base-
line, it represents an increase in grazing prevalence by 31%. At
12 months, the overlap between the grazers and “Uncontrolled
Eaters_12” was high, with 26 subjects (20.2% of the total cohort)
meeting criteria for both categories (P < 0.001). This number
represents 53.1% of the grazers and 78.8% of “Uncontrolled
Eaters_12.” As a result, these two groups shared many charac-
teristics compared to the remainder of the cohort. Grazers lost
a lower %WL; 17.3 ± 7.6% vs. 22.9 ± 8.4% and %EWL 40.9 ±
18.6% vs. 55.6 ± 20.0% (P < 0.001), reported less dietary restraint
(P = 0.031), greater hunger (P < 0.001) and disinhibition (P <
0.001), a higher number of daily eating episodes (P = 0.005), and
showed a statistical trend toward a higher total energy intake (P
= 0.057). More symptoms of depression (P = 0.024) and poorer
mental health–related QoL (P = 0.027) were also reported. Unlike
“Uncontrolled Eaters_12,” grazers reported a higher number of
gastrointestinal symptoms at 12-month follow-up (P = 0.013).
postsurgical emotional and situational eating triggers
Table 4 shows the extent to which different emotions and
situations triggered eating in certain groups, compared to the
remainder of the cohort. Fear of weight regain and the per-
ceived return of old eating habits were also assessed. Those
who reported baseline grazing remained a distinctive postsur-
gical group who (over)ate in response to numerous emotional
triggers, continued eating regardless of feeling full, were aware
of the return of old eating habits and fearful of weight regain.
Of the postsurgical groups, the “Uncontrolled Eaters_12” and
the subset with a high level of emotional disturbance related to
feelings of LOC reported eating in response to emotional trig-
gers, ignoring satiety cues and difficulty maintaining behavior
change. Those with NES at 12 months were also more likely to
eat in social situations and when tired.
presurgical factors predicting %Wl
A linear regression model was used to determine presurgical
factors predicting %WL. After controlling for baseline BMI,
age, gender, and an indirect measure of insulin resistance, all
baseline eating pathology groups, followed by baseline energy
intake, then eating-related behaviors, and finally psychologi-
cal variables were entered into the model. Forward and back-
ward linear regression identified baseline grazing, β = −0.385,
P < 0.001 as an independent predictor of %WL. In addition to a
higher baseline BMI, β = 0.236, P = 0.008, preoperative grazing
predicted 19.5% of variance in %WL.
table 3 comparison of the group who reported uncontrolled
eating with the remainder of the cohort 12 months after laGB
Age (years)44.1 ± 11.8b
44.8 ± 6.9
39.2 ± 6.5
37.0 ± 7.1
17.4 ± 8.2
52.6 ± 19.4
45.6 ± 11.4
44.1 ± 6.8
38.1 ± 5.6
34.3 ± 5.4*
22.0 ± 8.3**
42.5 ± 22.6**
BMI at 0 months (kg/m²)
BMI at 4 months (kg/m²)a
BMI at 12 months (kg/m²)
9 (5–19)6 (3–10)**
AD score 1.0 ± 1.0
3.3 ± 0.69
2.3 ± 0.85
47.5 ± 9.3
46.5 ± 7.8
10.9 ± 3.7
10.1 ± 3.1
0.86 ± 1.0
3.6 ± 0.64**
2.8 ± 0.76**
49.9 ± 10.0
49.8 ± 6.9*
13.7 ± 4.1**
4.8 ± 3.2***
Energy (Kj)4370 ± 1544
34.3 ± 5.6
21.3 ± 3.3
39.1 ± 5.6
3807 ± 1356*
30.3 ± 6.4**
22.8 ± 4.5
39.3 ± 7.4
Eat per day at 4 monthsc,d
3.0 (2.5–4)3.0 (2–3)*
Eat per day at 12 monthsc,d
3.0 (3–4) 3.0 (2–4)*
Statistical analysis using independent t-tests for continuous variables, χ2 for cat-
egorical variables, and Mann–Whitney U test for ordinal variables.
%EWL, percentage of excess weight lost; %WL, percentage of weight lost; AD,
appearance dissatisfaction; BDI, Beck depression Inventory; CHO, carbohydrate;
MCS, mental health component score; PCS, physical component score.
an = 93; bmean ± s.d. (all such values) unless specified; cData presented as
median (IQR); dFrequency of daily eating episodes. *P < 0.05, **P < 0.01, ***P
VOLUME 16 NUMBER 3 | MARCH 2008 | www.obesityjournal.org
behavior and psychology
postsurgical factors predicting %Wl
A linear regression model determined postoperative factors
most strongly predicting %WL. Baseline BMI, age, gender, and
insulin resistance were entered as controlling variables. Higher
appearance dissatisfaction, β = −0.278, P = 0.002, subjective
hunger, β = −0.254, P = 0.006, postsurgical grazing, β = −0.186,
P = 0.032, and total energy intake β = −0.182, P = 0.041 all
independently predicted a poorer %WL. In addition to base-
line BMI, β = 0.194, P = 0.029, these postoperative factors pre-
dicted 29.6% of variance in %WL.
This study assessed a range of eating behaviors before and
12 months after LAGB. Associations between presurgical and
postsurgical eating patterns, weight loss outcome, and psycho-
logical distress were investigated. First, irrespective of meas-
ured eating behavior, all groups achieved a significant weight
loss, far in advance of that achievable by behavioral (39,40) and
medical (41) weight loss therapies. Second, while variance in
eating behaviors was evident and linked to significant differ-
ences in weight outcomes, the extent of these differences may
not always be clinically significant.
Baseline BED as a distinct group, were not associated with
poorer postoperative weight loss. This finding agrees with most
(1,11,12,15,21,42–44) but not all (13,14,45) prospective studies.
However, preoperative BED were at higher risk of postsurgical
uncontrolled eating and grazing. During the first 6–12 post-
surgical months, over 60% of baseline BED reported recurrent
grazing, and 44% were considered uncontrolled eaters. More
than one third of baseline BED met criteria for both postop-
erative eating patterns. Several other studies support this ten-
dency for preoperative binge eaters to continue aberrant eating
behaviors after surgery (11,15,17,43,46). Given the difficulty
consuming objectively large amounts of food following gastric
restrictive surgery, Saunders has suggested that postsurgical
grazing may fulfill a similar function to binge eating (17).
Feelings of LOC related to eating have been reported as
early as four postsurgical months (15), and as late as 13.8
mean years after bariatric surgery (47). Kalarchian et al.
observed greater weight regain in 46% of subjects who
reported feelings of LOC associated with either objective or
subjective bulimic episodes between 2 and 7 years after roux-
en-Y gastric bypass (16). In the current study, the number
of “Uncontrolled Eaters” reduced after surgery; however, one
quarter of subjects were classified as uncontrolled eaters 12
months after LAGB. This group lost significantly less weight.
A number of factors may have influenced this outcome. The
“Uncontrolled Eaters_12” consumed more energy and pro-
portionately more fat, reported higher hunger and disinhibi-
tion, less dietary restraint, and more frequent eating episodes.
A higher frequency of eating in response to emotional trig-
gers was also reported. Others have observed this tendency
toward “emotional eating” among surgical patients (23,48).
Eating in response to emotions may stimulate a preference
for fatty and sweet foods (49–51).
Three quarters of “Uncontrolled Eaters_12” reported a high
level of emotional disturbance directly related to the experience
of loss of eating control. We have previously found that emo-
tional disturbance related to feelings of LOC was associated
with markers of psychological distress. This association was
consistent in persons reporting objective or subjective bulimic
episodes (18). In this study, this postoperative subgroup was
distinguished by poorer weight loss, younger age, higher dis-
satisfaction with appearance, and a tendency to be female.
The causality vs. counter-causality of the association remains
in question; however, these findings suggest that uncontrolled
eating after bariatric surgery is relatively common and linked
to poorer weight and psychological outcomes.
table 4 situations where, or reasons why, the disordered eating groups were more likely to consume types of foods or quantities
of food they knew to be not best for them, 12 months following laGB. Fear of weight gain and the return of “old eating habits”
among the groups was also assessed
Baseline BED Uncontrolled
12-month NES Baseline grazer12-month grazers
AnxietyNS 9.89 (P = 0.002)16.52 (P < 0.001)NS 10.26 (P = 0.001)6.33 (P = 0.012)
Fatigue4.46 (P = 0.035)15.01 (P < 0.001) NS4.48 (P = 0.034)16.33 (P < 0.001)NS
BoredomNS 13.48 (P < 0.001)8.41 (P = 0.004)NS 12.21 (P < 0.001)NS
StressNS 18.77 (P < 0.001) 13.61 (P < 0.001)NS 13.30 (P < 0.001)3.68 (P = 0.05)
Anger NS 11.60 (P = 0.001)6.38 (P = 0.012) NS 13.02 (P < 0.001)NS
Upset/depression NS9.48, (P = 0.002) 14.09 (P < 0.001) NS 4.97 (P = 0.026)NS
Habit 16.20 (P < 0.001)NSNS NS NSNS
When socializingNSNSNS 8.32 (P = 0.004)NSNS
Continue to eat
NS 26.69 (P < 0.001) 18.96 (P < 0.001)NS 30.71 (P < 0.001) 3.70 (P = 0.05)
Return of old
NS7.52 (P = 0.006)NSNS 10.73 (P = 0.001)NS
Fear weight gainNS10.36 (P = 0.001)15.53 (P < 0.001)NS 11.25 (P = 0.001)8.25 (P = 0.004)
Statistical analysis using χ2. Each group was compared to the remainder of the cohort.
BED, binge eating disorder; LOC, loss of control; NES, night eating syndrome; NS, not significant.
obesity | VOLUME 16 NUMBER 3 | MARCH 2008 621
behavior and psychology
After surgery, a significant number of subjects (20.2% of
the total cohort) were identified as both uncontrolled eaters
and grazers. This highlights a significant proportion of per-
sons who are likely to experience feelings of poor control over
eating behaviors, which include both larger portions of food
within distinct periods and smaller portions of food over
extended periods. Saunders has also observed an element
of poor control over grazing and defined this eating pattern
as “smaller, subjective episodes of overeating,” (17). Among
other factors, elevated hunger, which was identified as an
independent risk factor for poorer weight loss, was greater
in persons reporting these behaviors. Hunger suppression
and increased satiety are important weight loss mechanisms
after LAGB. Frequent clinic follow-up and band adjustments
to manage hunger are of prime importance. However, not
all LAGB recipients achieve optimal hunger control. Higher
markers of psychological distress and eating in response to
emotional cues were also present among uncontrolled eaters
and grazers. It is possible that those with poorly controlled
physical or emotional hunger are more likely to graze and
experience an LOC related to eating. These factors may in
turn promote a poorer psychological state.
Grazing was common before and after surgery. All but two
(5.9%) preoperative grazers continued this eating pattern after
LAGB. Although not statistically significant, grazing prevalence
was 31% higher after surgery compared to baseline. Not only does
gastric restriction permit the repeated intake of smaller amounts
of food, it may facilitate this eating pattern. Furthermore, both
preoperative and postoperative grazing independently predicted
poorer postsurgical weight loss. At 6 months after roux-en-Y
gastric bypass Saunders has also described persistent graz-
ing among those who reported this presurgical behavior (17).
Burgmer et al. reported that the prevalence of preoperative
grazing (“permanent eating”) was 19.5% among a cohort seek-
ing gastric restrictive surgery (6). Although this figure is similar
to ours, no difference in mean weight loss was found between
preoperative grazers and the remainder of the group one year
after surgery. Busetto et al. defined grazing as consumption of
“small quantities of foods repetitively between meals, typically
triggered by inactivity and/or loneliness” (12). This pattern was
present in 42.5% of surgical candidates but did not predict 3-year
weight outcomes after LAGB.
After surgery, the incidence of NES and nocturnal snack-
ing reduced significantly. The presence of baseline NES was
not associated with postoperative NES or any other eating
pattern. Interestingly, 6 of 10 subjects with postsurgical
NES commenced night eating after surgery. Adami et al.
prospectively assessed NES using similar criteria (20). Their
baseline prevalence estimate of 8% was similar to the 6%
reporting NES 3 years following BPD. Our findings do not
support the supposition of Adami et al. that NES remains
stable following obesity surgery. Research involving NES is
in its infancy and currently thwarted by inconsistent diag-
nostic criteria (19).
This manuscript represents one of the first attempts to
measure changes in eating behavior, and characterize “non-
normative” eating patterns after bariatric surgery. Given that
this was a primary aim, the lack of agreed group definitions
and substantial overlap between some groups is a limita-
tion. This study used a self-report survey followed by a
semistructured phone interview to assess eating behavior after
surgery. Although clinical interview may be considered the
method of choice to assess “disordered” eating behavior (52),
Saunders (17) notes that patients could be too ashamed to
admit feelings of LOC or aberrant eating behaviors to their
surgeon. Individuals experiencing a LOC may also be more
inclined to avoid clinical follow-up. In this study, we found
12-month non-respondents were more likely to have reported
presurgical BED, to have lost less weight and attended less
clinic appointments. Although this bias affects the ability to
generalize our results, it skews the study participants toward
less postsurgical eating pathology. The actual incidence of
deviant eating behaviors may have been higher. Strengths of
this study include the measurement of body weight in a clini-
cal setting, the use of validated questionnaires, paired meas-
urement of a wide range of eating patterns and behaviors, and
inclusion of several measures of non-eating-related psycho-
Limitations notwithstanding, this study highlights that
aberrant eating patterns before and after bariatric surgery are
associated with poorer postoperative outcomes. However, it
is important to acknowledge that all groups achieved a sig-
nificant weight reduction, and good evidence supports that
LAGB and roux-en-Y gastric bypass facilitate excellent sus-
tained weight loss in the medium term (53). Furthermore,
the difficulty of achieving and maintaining even minor weight
loss in those with BED is well documented (54,55). Therefore,
the best opportunity to attain a significant weight change in
obese binge eaters may be bariatric surgery. The focus on,
and sometimes exclusion of, presurgical BED appears mis-
directed. Yet preoperative binge eaters are a group at high
risk to become postoperative grazers and uncontrolled eat-
ers, and as such should receive close ongoing monitoring
after surgery. Young females may be a group at higher risk
of uncontrolled eating and psychological distress linked to
poorer weight outcomes.
Ongoing postoperative review, band adjustments, and clini-
cal management are imperative to optimize weight loss out-
comes and facilitate psychological well-being after LAGB.
Clearer characterization of favorable and unfavorable post-
surgical eating behaviors, and further definition of the clini-
cal significance of different patterns of uncontrolled eating and
grazing, is required. Future research should include subjects
undergoing other bariatric procedures and address the need
for reliable methods to assess postsurgical eating behavior and
empirically tested postsurgical intervention strategies to man-
age at-risk populations.
The authors thank the study participants for their time and involvement,
and the staff at the Centre for Obesity Research and Education (CORE),
and The Centre for Bariatric Surgery in Windsor, Victoria, for their ongoing
support and assistance.
622 Download full-text
VOLUME 16 NUMBER 3 | MARCH 2008 | www.obesityjournal.org
behavior and psychology
The authors declared no conflict of interest.
© 2008 The Obesity Society
1. Busetto L, Valente P, Pisent C et al. Eating pattern in the first year following
adjustable silicone gastric banding (ASGB) for morbid obesity. Int J Obes
Relat Metab Disord 1996;20:539–546.
2. Olbers T, Björkman S, Lindroos A et al. Body composition, dietary intake,
and energy expenditure after laparoscopic Roux-en-Y gastric bypass and
laparoscopic vertical banded gastroplasty: a randomized clinical trial.
Ann Surg 2006;244:715–722.
3. Brolin RL, Robertson LB, Kenler HA, Cody RP. Weight loss and dietary
intake after vertical banded gastroplasty and Roux-en-Y gastric bypass.
Ann Surg 1994;220:782–790.
4. Buchwald H, Avidor Y, Braunwald E et al. Bariatric surgery: a systematic
review and meta-analysis. JAMA 2004;292:1724–1737.
5. Dixon AF, Avidor Y, Braunwald E. Laparoscopic adjustable gastric
banding induces prolonged satiety: a randomized blind crossover study.
J Clin Endocrinol Metab 2005;90:813–819.
6. Burgmer R, Grigutsch K, Zipfel S et al. The influence of eating behavior
and eating pathology on weight loss after gastric restriction operations.
Obes Surg 2005;15:684–691.
7. Grace DM. Gastric restriction procedures for treating severe obesity.
Am J Clin Nutr 1992;55(2 Suppl):556S–559S.
8. Saunders R. Binge eating in gastric bypass patients before surgery.
Obes Surg 1999;9:72–6.
9. Sarwer DB, Wadden TA, Fabricatore AN. Psychosocial and behavioral
aspects of bariatric surgery. Obes Res 2005;13:639–48.
10. Diagnostic and statistical manual of mental disorders, 4th Edition (DSM-IV).
American Psychiatric Association: Washington DC, 1994.
11. Busetto L, Segato G, De Luca M et al. Weight loss and postoperative
complications in morbidly obese patients with binge eating disorder treated
by laparoscopic adjustable gastric banding. Obes Surg 2005;15:195–201.
12. Busetto L, Segato G, De Marchi F et al. Outcome predictors in morbidly
obese recipients of an adjustable gastric band. Obes Surg 2002;12:83–92.
13. Potoczna N, Branson R, Kral JG et al. Gene variants and binge eating as
predictors of comorbidity and outcome of treatment in severe obesity.
J Gastrointest Surg 2004;8:971–981; discussion 981–982.
14. Dymek MP, le Grange D, Neven K, Alverdy J. Quality of life and psychosocial
adjustment in patients after Roux-en-Y gastric bypass: a brief report.
Obes Surg 2001;11:32–39.
15. Kalarchian MA, Wilson GT, Brolin RE, Bradley L. Effects of bariatric
surgery on binge eating and related psychopathology. Eat Weight Disord
16. Kalarchian MA, Marcus MD, Wilson GT et al. Binge eating among gastric
bypass patients at long-term follow-up. Obes Surg 2002;12:270–275.
17. Saunders R. “Grazing”: a high-risk behavior. Obes Surg 2004;14:98–102.
18. Colles SL, Dixon JB, O’Brien PE. Loss of control is central to psychological
disturbance associated with binge eating disorder. Obesity, this issue.
19. Colles SL, Dixon JB. Night eating syndrome: impact on bariatric surgery.
Obes Surg 2006;16:811–820.
20. Adami GF, Meneghelli A, Scopinaro N. Night eating and binge eating
disorder in obese patients. Int J Eat Disord 1999;25:335–338.
21. Powers PS, Perez A, Boyd F, Rosemurgy A. Eating pathology before
and after bariatric surgery: a prospective study. Int J Eat Disord
22. Rand CS, Macgregor AM, Stunkard AJ. The night eating syndrome in the
general population and among postoperative obesity surgery patients.
Int J Eat Disord 1997;22:65–69.
23. Glinski J, Wetzler S, Goodman E. The psychology of gastric bypass surgery.
Obes Surg 2001;11:581–588.
24. Favretti F, O’Brien PE, Dixon JB. Patient management after LAP-BAND
placement. Am J Surg 2002;184:S38–S41.
25. Spitzer RL, Devlin MJ, Walsh BT et al. Binge eating disorder: a multisite field
trial of the diagnostic criteria. Int J Eat Disord 1992;11:191–203.
26. Spitzer RL, Yanovski S, Wadden T et al. Binge eating disorder: its further
validation in a multisite study. Int J Eat Disord 1993;13:137–153.
27. Stunkard A, Berkowitz R, Wadden T et al. Binge eating disorder and the
night-eating syndrome. Int J Obes Relat Metab Disord 1996;20:1–6.
28. Hodge A, Patterson AJ, Brown WJ, Ireland P, Giles G. The Anti Cancer
Council of Victoria FFQ: relative validity of nutrient intakes compared with
weighed food records in young to middle-aged women in a study of iron
supplementation. Aust NZ J Public Health 2000;24:576–583.
29. Hodge A, Patterson AJ, Brown WJ, Ireland P, Giles G. Erratum: The Anti
Cancer Council of Victoria FFQ: relative validity of nutrient intakes compared
with weighed food records in young to middle-aged women in a study of
iron supplementation. Aust NZ J Public Health 2003;27:468.
30. Stunkard AJ, Messick S. The three-factor eating questionnaire to
measure dietary restraint, disinhibition and hunger. J Psychosom Res
31. Beck AT, Steer RA. Manual for the Beck Depression Inventory. Psychological
Corporation: San Antonio TX, 1993.
32. Smarr KL. Measures of depression and depressive symptoms.
Arthritis Rheum 2003;49:S134–S146.
33. Cash T. Multidimensional body-self relations questionnaire. 02/94 ed.
MBSRQ Users Manual 1994. Old Dominion University: Norfolk-Virginia,
34. Dixon JB, Dixon ME, O’Brien PE. Body image: appearance orientation
and evaluation in the severely obese. Changes with weight loss. Obes Surg
35. Ware J. SF-36 Health Survey: Manual and Interpretation Guide, 1997.
The Health institute, New England Medical Center: Boston, 1997.
36. Ware J. SF-36 Physical and Mental Health Summary Scales: A User’s
Manual, 1994. The Health Institute, New England Medical Center: Boston.
37. Dixon JB, O’Brien PE. Selecting the optimal patient for LAP-BAND
placement. Am J Surg 2002;184:S17–S20.
38. Colles SL, Dixon JB, O’Brien PE. Night eating syndrome and nocturnal
eating: association with obesity, binge eating and psychological distress.
Int J Obes, 2007;31(11):1722–30.
39. Anderson JW, Konz EC, Frederich RC, Wood CL. Long-term weight-loss
maintenance: a meta-analysis of US studies. Am J Clin Nutr
40. Astrup A. Macronutrient balances and obesity: the role of diet and physical
activity. Public Health Nutr 1999;2:341–347.
41. Padwal R, Li SK, Lau DC. Long-term pharmacotherapy for overweight and
obesity: a systematic review and meta-analysis of randomized controlled
trials. Int J Obes Relat Metab Disord, 2003;27:1437–1446.
42. Boan J, Kolotkin RL, Westman EC, McMahon RL, Grant JP. Binge eating,
quality of life and physical activity improve after Roux-en-Y gastric bypass
for morbid obesity. Obes Surg 2004;14:341–348.
43. Lang T, Hauser R, Buddeberg C, Klaghofer R. Impact of gastric banding on
eating behavior and weight. Obes Surg 2002;12:100–107.
44. Malone M, Alger-Mayer S. Binge status and quality of life after gastric
bypass surgery: a one-year study. Obes Res 2004;12:473–481.
45. Green AE, Dymek-Valentine M, Pytluk S, Le Grange D, Alverdy J.
Psychosocial outcome of gastric bypass surgery for patients with and
without binge eating. Obes Surg 2004;14:975–985.
46. Hsu LK, Sullivan SP, Benotti PN. Eating disturbances and outcome of gastric
bypass surgery: a pilot study. Int J Eat Disord 1997;21:385–390.
47. de Zwaan M, Lancaster KL, Mitchell JE et al. Health-related quality of life
in morbidly obese patients: effect of gastric bypass surgery. Obes Surg
48. Walfish S. Self-assessed emotional factors contributing to increased weight
gain in pre-surgical bariatric patients. Obes Surg 2004;14:1402–1405.
49. Grunberg NE, Straub RO. The role of gender and taste class in the effects of
stress on eating. Health Psychol 1992;11:97–100.
50. Oliver G, Wardle J, Gibson EL. Stress and food choice: a laboratory study.
Psychosom Med 2000;62:853–865.
51. Epel E, Lapidus R, McEwen B, Brownell K. Stress may add bite to appetite
in women: a laboratory study of stress-induced cortisol and eating behavior.
52. Cooper Z, Fairburn CG. The eating disorder examination: a semi-structures
interview for the assessment of the specific psychopathology of eating
disorders. Int J Eat Disord 1987;6:1–8.
53. O’Brien PE, McPhail T, Chaston TB, Dixon JB. Systematic review
of medium-term weight loss after bariatric operations. Obes Surg
54. Grilo CM, Masheb RM, Salant SL. Cognitive behavioral therapy guided
self-help and orlistat for the treatment of binge eating disorder: a
randomized, double-blind, placebo-controlled trial. Biol Psychiatry
55. Devlin MJ, Goldfein JA, Petkova E et al. Cognitive behavioral therapy and
fluoxetine as adjuncts to group behavioral therapy for binge eating disorder.
Obes Res 2005;13:1077–1088.